1. Field of the Invention
This invention relates to a liquid jet recording device, and particularly to a novel liquid jet recording device of a high density multi-orifice type.
2. Description of the Prior Art
Liquid jet methods are highlighted in these days, because they are capable of high speed recording with very little, or even negligible, noise generation at the time of recording, and also because recording is possible on so called plain paper without any specific treatment of fixation.
Among them, for example a liquid jet recording method as disclosed in German Laid-open specification (DOLS) No. 2843064 has a specific feature different from other methods in which heat energy is permitted to act on a liquid to obtain a driving force for discharging of liquid droplets.
That is, the recording method disclosed in DOLS No. 2843064 is specific in that a liquid which has received the action of heat energy will undergo a change of state accompanied by an abrupt increase of volume, whereby the liquid is discharged by the active force based on the change of state through the orifice at the tip of the recording head portion to form flying droplets, and the droplets are then attached on a recording member to effect recording.
In particular, the liquid jet recording method as disclosed in the DOLS No. 2843064 specification can be very effectively applied to the so called drop on demand recording method, and furthermore it can be used to realize a recording head portion made into a high density multi-orifice of full-line type, thus providing images of high resolution and high quality at a high speed.
The recording head portion in the device to be applied with the above recording method is provided with a liquid discharging portion, having orifices provided for discharging a liquid, liquid channels communicating with the orifices and constituted partly of heat acting portions which are parts at which heat energy acts on liquid for discharging liquid droplets and an electrothermal transducer as a means for generation of heat energy.
The electrothermal transducer is provided with a pair of electrodes and a heat-generating resistance layer which is connected to these electrodes and has a heat-generating region (heat-generating portion) between these electrodes.
As described above, according to the liquid jet recording method disclosed in the DOLS, it is highly probable to realize a liquid jet recording device of full-line type made into a high density multi-orifice, but there are not a few problems before manufacturing such a device as commercial product.
For example, when the orifice density is 8 pieces/mm with a full line of the shorter side of A4 size, namely a full line type of 210 mm, the orifice number is 1680, and electrothermal transducers are also required to be provided in equal number at high density, thereby giving arise to some points to be solved with respect to reliability of the device, productivity and mass production. Also, 1680 orifices are required to be worked with a very high working technique and have a very high precision in order to control the flying direction, flying speed as well as sizes of liquid droplets discharged from respective orifices as desired. Further, at present it is demanded that compactness of the device per se and lowering of failure probability should also be satisfied.
On the other hand, in order to obtain an image of high quality in recording by means of a liquid jet recording device of a high density multi-orifice type as described above, the following three conditions with respect to uniformity are required to be provided:
(1) Uniformity in size of liquid droplets discharged repeatedly through the same orifice as well as uniformity in size of liquid droplets between orifices should be high.
(2) Uniformity in flying direction between orifices should be high.
(3) Uniformity in the discharging speed of liquid droplets discharged repeatedly through the same orifice as well as uniformity in liquid droplet discharging speed between orifices should be high.
In this respect, there remains room for improvement of the multi-orifice type liquid jet recording device of the prior art.